Hello everybody!
I've found a ton of useful information on this forum in the process of researching this hack so I figured I'd share what I managed to accomplish with you.
I found a lot of info about using the CD to mainboard ribbon to get audio, but my CD player is broken and if I was going to replace that, I may as well get a new faceplate and head unit with an aux in built in.
Now I have a nice little 3.5mm jack in the cubby above the stereo that cuts out the radio audio when a plug is inserted and plays the audio from your device nice and clearly.
That's pretty bad ass! I'm really nervous about soldering as I don't have much practice but I really want aux-in! I hate the FM transmitter for my iPhone.